uniform mat4 u_mvpMatrix;

uniform vec3 texSize;

attribute vec4 a_position;

attribute vec3 a_texCoord;

varying vec2 texStep; // could be uniform

varying vec2 coord2pi;

varying vec2 texCoord;

varying vec2 videoCoord;

const float pi = 3.1415927;

const float pi2 = 2.0 * pi;

void main()

{

	gl_Position = u_mvpMatrix * a_position;

	texCoord = a_texCoord.xy;

	coord2pi = a_texCoord.xy * texSize.xy * pi2;

	texStep = 1.0 / texSize.xy;

#if SUPERIMPOSE

	videoCoord = a_texCoord.xz;

#endif

}